1. Field of the Invention
The present invention relates to an embedded coding unit and embedded coding method, a decoding unit and decoding method, and a storage medium, and particularly relates to an embedded coding unit and embedded coding method, a decoding unit and decoding method, and a storage medium, whereby information can be embedded in images without deteriorating the image quality of the decoded image and also without increasing the amount of data.
2. Description of the Related Art
One of the techniques of embedding information in data without increasing the amount of data is to convert the least significant bit or the lower two bits of digital audio data for example, into embedded information. With this technique, advantage is taken of the fact that the lower bits of digital audio data do not significantly influence sound quality, and accordingly the lower bits are simply replaced with the information to be embedded. Accordingly, when digital audio data wherein information has been embedded is reproduced, the lower bits are output as is without being restored to the original state. That is, it is difficult to restore the lower bits embedded with information to the original state, and also, the lower bits do not significantly influence the sound quality, so the digital audio data is output in the state of containing information embedded therein.
However, according to the above-described technique, data which differs from the original data is output. Accordingly, there is some degree of effect on the sound quality in the event that the data is audio data, or on the image quality in the event that the data is video data.